A Protestant extremist group said its gunmen killed a leader of the Protestant Ulster Defense Assn. because he betrayed the association’s cause in Northern Ireland. The outlawed Ulster Freedom Fighters said James Craig, 47, was the target in the Saturday shooting in a Belfast bar. A second man was killed and four others were wounded in the gunfire. Initially, guerrillas of the outlawed Irish Republican Army were suspected. The ruling council of the defense association last year had ordered an investigation into Craig’s activities. It said he was accused of skimming money from the estimated $5.2 million raised annually through rackets operated by Protestant extremists. The Ulster Freedom Fighters are believed to be the military arm of the defense association, a Protestant vigilante group.